The present invention relates to an armor piercing shell of the kind comprising a shaped or hollow charge and an impact contact member placed in the nose cone of the shell and arranged to provide electrical contact for initiation of the hollow charge upon impact of the shell against a target.
Different types of anti-tank ammunition used for combating of armored vehicles, particularly tanks, are known in the prior art. Such ammunition is designed to penetrate even thick armor plates. Armor piercing shells comprise a special type of anti-tank ammunition which is provided with a hollow charge warhead. In principle, a hollow charge comprises an outer casing, a metal cone and an explosive. When the explosive detonates, the metal cone is squeezed together and a metal jet is formed which, with great force, penetrates even very thick and hard armor. Due to its good effect in armored targets, the hollow charges have long constituted a serious threat to armored vehicles.
In consequence of the development that has taken place on the protection side through the introduction of composite armor, active armor, etc., the importance of improving the penetrability of the warhead has, however, increased. Developments have therefore led to increasingly longer and heavier hollow charges. In certain cases this can be accepted, typically for all-target shells etc., but for severely weight-optimized designs, with limited space etc., this method is inappropriate. With state-of-the-art technique, therefore, limit has been reached in practice as regards the length and weight of the charges.
In order to increase the penetrability, hollow charges differing from conventional hollow charges have also been developed in recent times. These charges can, for instance, comprise an auxiliary body disposed in front of or integrated with the metal cone of the charge so that upon initiation of the charge it generates a slug which follows behind the actual penetration jet and penetrates and enlarges the hole made by the penetration jet. Alternatively, the hollow charge may have a warhead with two complete hollow charges, so-called tandem hollow charges, which after the projectile is fired accompany each other as an integral unit during the greater part of the travel towards the target, only to separate at a predetermined distance from this and to continue towards the target at mutually slightly different velocities along largely the same trajectory and thereafter to hit the target with a sufficient interval of time to enable the charge which reaches the target first to detonate the explosive in any active armour before the second charge reaches the target, so that this latter charge penetration jet is able to work without disturbance and also is assisted by the penetration work already performed by the first charge which has already detonated within the same confined area of the charge. See Swedish patent application No. 8302727-6.
In order to function in the intended manner each of the two hollow charges in such a tandem hollow charge must have its own ignition system with associated safety device. To separate the two hollow charges, it is also necessary to have a smaller parting charge, e.g. a powder charge, between the two charges in order to impart to each of these its own velocity change.
It is realized that the penetrating ability against active armor can be increased significantly through two such interacting charges. It is also realized, however, that the warhead of the projectile will be significantly more expensive with two complete hollow charges, each including its own ignition system and a parting charge.
The object of the present invention is therefore to provide an armor piercing explosive shell in which improved penetrative performance against active armor has been accomplished in a considerably simpler manner. Instead of providing an extra hollow charge which is made to detonate the explosive in an active armor so that the following hollow charge is then able to work without disturbance, the invention is based on the ability of the nose cone of the shell to mechanically penetrate the active armor before the hollow charge is initiated. This means that the penetration jet of the hollow charge can pass undisturbed by the active armor so that full penetrability is obtained in the main target.
A further object of the invention is to provide an armor piercing explosive shell which can be manufactured by modification of already existing anti-tank ammunition, typically 9-cm ammunition.
According to the present invention the nose cone of the shell has a reinforced tip for mechanical penetration of active armor and the impact contact member is so positioned in the nose cone that contact is obtained only when the reinforced tip has penetrated aside the active armor without detonating.
Preferably, the tip of the nose cone is solid and sharper than in conventional anti-tank shells and the impact contact member is not extended all the way to the tip of the shell. By this means, the delay is accomplished which is required in order for the shell to have time to penetrate the active armor before the hollow charge is initiated.
Preferably, the casing in the nose cone cap of the shell is also made of a harder material than in a conventional shell, for example a high-strength steel.
In the present invention only the front part of the shell, the nose cone or cap, is modified so that existing ammunition can easily be adapted by replacement of the nose cone or cap. A certain increase in the volume of the shell of the nose cone is obtained, but this is not believed to have any appreciable influence on the properties of the shell.
The invention will now be described in more detail with reference to the accompanying drawings, in which